New Generation Connector Finish

Posted on:1/1/1999

AMP develops a high-performance finish for its connector contacts...

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AMP, together with Lucent Technologies, developed a palladium/cobalt connector contact finish.

If you drive any type of vehicle, call your office from a mobile telephone, watch the news on television or open the refrigerator looking for leftovers, you have probably connected with products manufactured by AMP Inc., Harrisburg, Pennsylvania. AMP (Aero-Marine Products) is a leading supplier of electrical and electronic connection devices, which include products from traditional connectors and tooling to cutting-edge technologies in fiber optics and wireless communications.

Recently, AMP took the wraps off a new plating finish material for its connector contacts, palladium/cobalt. AMP conducted studies indicating that contacts finished with palladium/cobalt provide better performance than palladium/nickel plated connectors at about the same cost.

According to Dr. James Sykes, director of AMP Global Technology, the company sees palladium/cobalt as the next generation of connector contact finishes. "We have been developing palladium/cobalt finishes at our manufacturing and research facilities for about two years," he said. "The work has involved developing and refining the formulation and process for applying the electroplating solutions." The technology was licensed from the electrochemical arm of Lucent Technologies.

AMP tests demonstrate that palladium/cobalt offers both performance and processing advantages over palladium/nickel, which has stood as the cost-effective finish of choice for about 20 years. "Palladium/cobalt has greater durability," Dr. Sykes said. "Hardness has a significant impact on durability; its hardness is greater than palladium/nickel or hardened gold. Durability is especially important for connectors that undergo numerous connect/disconnect cycles during their life span." Other performance parameters, such as contact resistance and fretting corrosion resistance, run about the same for the two alloys.

Another advantage concerns processing quality control. AMP experienced a higher degree of thickness control with palladium/cobalt, providing a smoother and more uniform finish. The connector contacts typically have a nickel barrier layer between the copper contact and the top-plate finishes. The nickel barrier layer prevents the copper from diffusing through the palladium to the surface. It also interferes with many thickness measurements of palladium/nickel. Thickness measurement of palladium/cobalt finishes do not suffer from this interference problem.

AMP plates the copper contacts of connectors to minimize corrosion and optimize electrical contact. Existing high-performance plating systems, in order of decreasing costs, are gold, palladium and palladium/nickel. In addition, a plated nickel layer always acts as a barrier between the copper contacts and the finish layer, preventing diffusion of the copper. A thin, one to five microinch, final layer of gold flash is generally recommended with all palladium systems.

Palladium, a noble metal, is less expensive to process than gold. However, during processing, palladium can absorb hydrogen from the plating baths. Because of this, localized brittle deposits form, leading to a tendency for cracks to develop in the contact surface. Palladium also reacts with carbon from the air to form an insulating polymer. This works well for an automotive exhaust system, but must be avoided for a connector contact.

Alloying palladium with nickel minimizes these problems, and reduces plating costs even further. Nickel makes the contact less noble and more prone to corrosion. The presence of nickel also complicates thickness measurements during processing. To offset thickness uncertainty, companies often plate more metal on the contacts than strictly necessary. Because of this, AMP and Lucent Technologies developed palladium/cobalt alloy plating.

AMP at a Glance

AMP Inc. opened its doors for business in 1941. The U.S. government was its first customer. Since then the company has diversified and thrived. Sales have grown from $32 million in 1956 to sales of nearly $6 billion today.

The first overseas operation began in France in 1952. Today AMP employs 47,000 in 53 countries throughout the Americas, Europe and Asia-Pacific regions. The company serves 90,000 customer locations with 800,000-plus part numbers in more than 470 product lines.

The company spends 10% of its sales on research, development and engineering of its products. Principal products include electrical and electronic connectors, terminals and splices, cable and cable assemblies, printed wiring boards, panel assemblies, networking/premise-wiring systems, optical fiber and electro-optical products, components for wireless communications systems and application tooling.

Along with being a global corporation, AMP is also a global citizen. AMP holds its worldwide operations to stringent environmental standards and has worked to slow energy consumption. It reaches out directly to the people in the regions where it does business through the AMP Foundation, awarding more than $1 million each year in grants that benefit educational and art programs as well as social-service agencies. To learn more about the company, check out its website www.amp.com.

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